From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kamezawa Hiroyuki Subject: Re: [PATCH 1/8] cgroup: add cgroup->id Date: Tue, 20 Nov 2012 16:11:38 +0900 Message-ID: <50AB2D2A.1040604@jp.fujitsu.com> References: <1353093624-22608-1-git-send-email-tj@kernel.org> <1353093624-22608-2-git-send-email-tj@kernel.org> <50AB086E.70901@jp.fujitsu.com> <20121120053112.GE25790@mtj.dyndns.org> <50AB2BCF.2050204@jp.fujitsu.com> <20121120070851.GG25790@mtj.dyndns.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20121120070851.GG25790-9pTldWuhBndy/B6EtB590w@public.gmane.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Tejun Heo Cc: nhorman-2XuSBdqkA4R54TAoqtyWWQ@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, daniel.wagner-98C5kh4wR6ohFhg+JK9F0w@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, john.r.fastabend-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, srivatsa.bhat-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org (2012/11/20 16:08), Tejun Heo wrote: > Hello, Kamezawa. > > On Tue, Nov 20, 2012 at 04:05:51PM +0900, Kamezawa Hiroyuki wrote: >> BTW, css's ID was limited to 65535 to be encoded in 2bytes. >> If we use INT, this will increase size of swap_cgroup. >> (2bytes per page => 4bytes per page) It's preallocated at swapon() >> because allocating memory dynamically when we swap a memory is not good. >> >> Do we really need 4bytes for ID ? If so, swap_cgroup should be totally re-designed. > > That's a memcg restriction which shouldn't have been imposed on cgroup > core from the beginning. What memcg should do is rejecting to become > online from ->css_onilne() if cgrp->id is out of the range it can > handle. > Hmm. I'll think a little and consider a patch to remove memcg's refcnt. Thanks, -Kame From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752091Ab2KTHMI (ORCPT ); Tue, 20 Nov 2012 02:12:08 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:45617 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751122Ab2KTHMG (ORCPT ); Tue, 20 Nov 2012 02:12:06 -0500 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.8.4 Message-ID: <50AB2D2A.1040604@jp.fujitsu.com> Date: Tue, 20 Nov 2012 16:11:38 +0900 From: Kamezawa Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:16.0) Gecko/20121026 Thunderbird/16.0.2 MIME-Version: 1.0 To: Tejun Heo CC: daniel.wagner@bmw-carit.de, srivatsa.bhat@linux.vnet.ibm.com, john.r.fastabend@intel.com, nhorman@tuxdriver.com, lizefan@huawei.com, containers@lists.linux-foundation.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/8] cgroup: add cgroup->id References: <1353093624-22608-1-git-send-email-tj@kernel.org> <1353093624-22608-2-git-send-email-tj@kernel.org> <50AB086E.70901@jp.fujitsu.com> <20121120053112.GE25790@mtj.dyndns.org> <50AB2BCF.2050204@jp.fujitsu.com> <20121120070851.GG25790@mtj.dyndns.org> In-Reply-To: <20121120070851.GG25790@mtj.dyndns.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2012/11/20 16:08), Tejun Heo wrote: > Hello, Kamezawa. > > On Tue, Nov 20, 2012 at 04:05:51PM +0900, Kamezawa Hiroyuki wrote: >> BTW, css's ID was limited to 65535 to be encoded in 2bytes. >> If we use INT, this will increase size of swap_cgroup. >> (2bytes per page => 4bytes per page) It's preallocated at swapon() >> because allocating memory dynamically when we swap a memory is not good. >> >> Do we really need 4bytes for ID ? If so, swap_cgroup should be totally re-designed. > > That's a memcg restriction which shouldn't have been imposed on cgroup > core from the beginning. What memcg should do is rejecting to become > online from ->css_onilne() if cgrp->id is out of the range it can > handle. > Hmm. I'll think a little and consider a patch to remove memcg's refcnt. Thanks, -Kame